Freeing up space · Storage Profile, charts and Home
What does Compute exact sizes do in the Storage Profile?
Short answer: It replaces the quick estimate in What's stored with precise, measured bytes per file category. It takes a little longer and is paced around your own work.
The What's stored section shows your files by category and size from quick system signals. Tap Compute exact sizes and Storage Studio measures the precise bytes in each category instead.
It takes longer than the quick view, and like Storage Studio's other background work it's paced so your own work comes first. See What is the Storage Profile?